/Engine/Source/Runtime/Slate/Public/Framework/Docking/TabManager.h
It sets the desired (or all) tabs in theFTabManager::FLayoutNodeto the desired value.
void SetTabsTo ( const [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [FTabManager::FLayoutNode](API\Runtime\Slate\Framework\Docking\FTabManager\FLayoutNode) > & SomeNode, const [ETabState::Type](API\Runtime\Slate\Framework\Docking\ETabState__Type) NewTabState, const [ETabState::Type](API\Runtime\Slate\Framework\Docking\ETabState__Type) OriginalTabState ) const